Thermostat



2 Sheets-Sheet 1. G. L. GRAY.

THERMOSTAT.

(No Model.)

Patented Oct, 6, 1885.

N TEES Pholo-Lithognphcr. v

UNITED STATES PATENT OFFICE.

GEORGE L. GRAY, OF CHICAGO, ILLINOIS.

,TH E R M OSTAT.

SPECIFICATION forming part of Letters Patent No. 327,941, dated October6, 1885.

Application filed December 4, 1884. Serial No. 149,458. (No model.)

To all whom it may concern:

Be it known that I, GEORGE L. GRAY, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Incubators, of which thefollowing is a specification, to wit: 7

This invention relates to an improvement in thermostats; and it consistsin certain peculiarities of the construction and arrangement of thesame, substantially as will be hereinafter more fully set forth andclaimed.

In order to enable others skilled in the art to which my inventionpertains to make and use the same, I will now proceed to describe itsconstruction and operation, referring to the accompanying drawings, inwhich Figures 1 and 2 are respectively a perspective and a sectionalview of an incubator, showing one use to which my thermostat isapplicable, and Fig. 3 represents the thermostat itself arranged forthis application.

A represents the main body of an incubator, which is formed with hollowwalls filled with water, as at a, and is heated by a lamp, B, placed inany convenient position, but preferably, as herein shown, beneath thehatchingchamber. It is important in an incubator to retain an eventemperature at the given point, and to automatically regulate theheating device so that this temperature shall not be exceeded or theheating device entirely extinguished, and thereby necessitate a carefulwatch of the device to prevent spoiling the eggs.

The lamp B is formed with a depression, f, surrounding the base of theburner-support, and when in use this depression is filled with water orother liquid and the burner inserted in the lower end of a smoke-escapeand heating tube, b. This tube passes up through the hollow wall orwater-chamber a, and serves to heat the water which surrounds thehatchingchamber. The lower end of the flue b rests in thesealing-depression f of the lamp and effectually prevents the admissionof any air at that point.

To supply air in proper quantity, I connect with the fine 1) below thelamp-burner a supply-tube, B, which extends upward and has its endinverted over an offset of the main body and the water which itcontains. The air which feeds the flame must enter at this point andpass through the tube B to the lamp, and thence thesmoke and heated airpass off throu gh the flue b. It will readily be seen that when thewater in the hollow body becomes heated it expands and rises in theoffset and nearly closes the end of the supply-pipe. This cuts off aportion of the amount of air supplied to the flame and it burns withless force. The balance is thus soon obtained and an even temperaturemaintained at the desired point.

The outer end of the supply-pipe is provided with a movable section, a",which is adj usted nearer to or farther from the exposed surface of thewater, as desired, to regulate the degree of heat obtained. Should thewater become hot enough to entirely close the supply-tube, it is evidentthat the lamp would go entirely out, and to prevent this I connect thesupply-tube B, by a pipe, 0. with a somewhat higher point on theescape-flue b. When the supply of fresh air is nearly or quite cut off,the heated air, instead of passing off, circulates around through theconnection 0 and supply B again to the flame, and a sufficient quantityof fresh air is drawn in at the outer end of the escape-flue to keep theflame from going out or smoking. This connection C may be placed at anypoint desired upon the supply and escape pipes; but a downward draft ofair must be maintained in the supply-pipe.

To insure a sufficient supply of fresh air to prevent the lamp fromgoing entirely out when the endof pipe B is closed, I prefer to form oneor more small perforations, c, in the pipe 0, which will admit justsuflicient fresh air to effect the desired object. I also prefer toconmeet the pipe 0 with the flue b at a higher point than with thesupply B, and thus cause the smoke and products of combustion to passdirectly off without any portion being drawn back to the lamp till theend of the supply is partially closed.

I have shown this device as applied to an incubator, for which it isespecially designed; but it may be used for the distillation of liquids,and for any other purpose where it is important that an even temperatureshould be maintained; and I do not therefore desire to be confined tothe particular arrangementherein shown, but shall vary this ascircumstances shall dictate, preserving the main principles of thedevice, which insure its proper operation, as described.

Having thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent, is-

1. In a thermostat, aheating device provided with a smoke-escape pipe,and an air-supply pipe, which is closed at a given temperature, incombination with a pipe connecting the escape with the supply, wherebythe heated air is drawn into the flame again when the supply is whollyor partially closed, substantially as and for the purpose set forth. I

V 2. In a thermostat, a heating device provided with asmoke-escape andan air-supply, the latter of which is closed at a given temperature, incombination with a connecting-pipe,

GEORGE L. GRAY.

Witnesses:

W. O. MOARTHUR, CHAS. KRESSMANN.

